Pedestal for a treatment chair

ABSTRACT

A pedestal construction for a treatment chair, such as a dental chair, having a standard with electrically operated components thereon, such as electrical controls and motors for elevating, tilting and/or traversing the seat, backrest and/or leg rest of the chair, and wherein the pedestal comprises a base with a turntable rotatably mounted thereon, and on which the standard is supported. The base and turntable are constructed so as to accommodate therein portions of electrical conductor means which extend from a source through the base and the turntable to electrical components above the turntable in such a manner as to permit nearly a full revolution of adjustment of the turntable with the standard of the chair thereon without placing the conductor means under undue strain, and also obviating the need for providing a substantial coiled length of a conductor cable on the floor adjacent the chair in order to permit such adjustment of the turntable.

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Lefiler States Patent 1 PEDESTAL FOR A TREATMENT CHAIR [75] Inventor: Dennis Frank Leffler, Charlotte,

[73] Assignee: Pelton & Crane Company,

Charlotte, NC.

[22] Filed: May 17, 1973 [21] Appl. No.: 361,229

[52] 11.8. C1 248/418, 188/78, 248/425 [51] Int. Cl. F16m 11/30 [58] Field of Search 248/425, 415, 418;

297/330, 311, 344, 349, 71; 108/142, 23; 2ll/1.5; 188/78, 74; 240/DIG. 2, 73 B1, 81 BA, 81 BC, 81 BD, 81 BE Primary Examiner-Marion Parsons, Jr. Attorney, Agent, or Firm-Parrott, Bell, Seltzer, Park & Gibson [5 7] ABSTRACT A pedestal construction for a treatment chair, such as a dental chair, having a standard with electrically operated components thereon, such as electrical controls and motors for elevating, tilting and/or traversing the seat, backrest and/or leg rest of the chair, and wherein the pedestal comprises a base with a turntable rotatably mounted thereon, and on which the standard is supported. The base and turntable are constructed so as to accommodate therein portions of electrical conductor means which extend from a source through the base and the turntable to electrical components above the turntable in such a manner as to permit nearly a full revolution of adjustment of the turntable with the standard of the chair thereon without placing the conductor means under undue strain, and also obviating the need for providing a substantial coiled length of a conductor cable on the floor adjacent the chair in order to permit such adjustment of the turntable.

12 Claims, 9 Drawing Figures PEDESTAL FOR A TREATMENT CHAIR This invention relates to treatment chairs, such as are used by dentists, chiropractors, beauticians and the like, and the invention is particularly concerned with an improved pedestal construction for chairs of the type having electrically operable components, such as an elevatable and/or traversable seat, a tiltable backrest and/or a tiltable leg rest. Generally, such treatment chairs are provided with a suitable standard on which the seat is mounted, and which standard is mounted on a turntable adjustable about a substantially vertical axis on a pedestal base.

Various problems have been presented heretofore in connecting the electrical components and associated electrical circuitry of such treatment chairs to an electrical outlet or receptacle while permitting adjustment of the turntable and the chair supported thereon relative to the pedestal base. One way in which this problem has been overcome to some extent, and which has permitted substantially unrestricted adjustment of the turntable and the chair carried thereby about a vertical axis, has been to provide a large coil of surplus electrical conductor cable adjacent the chair and interposed between the electrical receptacle and the chair so that the electrical cable could simply wrap around the standard of the chair during such adjustment. However, such surplus of electrical cable on the floor adjacent the treatment chair not only is unsightly, but it also presents a hazard in that the attendant may slip on or trip over the surplus coil of electrical cable.

In order to obviate the need for providing a surplus coil of electrical cable adjacent the treatment chair, it has been proposed-to extend a length of electrical cable from the electrical outlet or receptacle through a portion of the pedestal base and through the turntable to the various electrically operable components of the treatment chair above the turntable. However, such attempts have not been satisfactory because they have either required substantially complicated and expensive ancillary equipment, such as electrical contact brushes and slip rings, or the cable has been extended through the base and turntable of the pedestal in such a manner that adjustment of the turntable and the chair thereon about the vertical axis thereof could only extend through about one-fourth to one-half a revolution, since otherwise, an undesirable twisting of the conductors in the electrical cable would occur which, in time, would rupture the electrical conductor or the insulating covering thereon thereby interrupting the operation of the electrical components of the chair and presenting an electrical hazard.

It is therefore an object of this invention to provide a simple and easily assembled pedestal construction for a treatment chair of the character described and wherein the turntable and base of the pedestal construction are adapted to accommodate therein portions of electrical conductor means which extend through both the base and the turntable to electrical components above the turntable while permitting nearly a full revolution of adjustment of the chair and its supporting turntable about a substantially vertical axis without the need for placing the conductor means under excessive strain and also obviating the need for providing a surplus coiled length of a conductor cable on the floor adjacent the treatment chair.

It is a more specific object of this invention to provide a pedestal construction for a treatment chair of the type described, which pedestal construction comprises a base adapted to rest upon a supporting floor and having a substantially circular recess in its upper face in which a turntable, with the standard of the chair secured thereon, is rotatably supported on an antifriction bearing means, and wherein an annular fastening means surrounds the rotational axis of the turntable and includes means for maintaining the turntable in the recess against its antifriction bearing means while permitting rotation of the turntable: and the standard thereon relativeto the base. The turntable and the fastening means define an axial opening therethrough, and the base also has a passageway therein adjacent the fastening means and communicating with the axial opening, with the passageway extending outwardly from the axial opening along the bottom wall of the recess in the pedestal base and forming an orifice communicating with the atmosphere at a point radially outwardly of the turntable so that a medial portion of an electrical conductor means extending from the electrically operable components of the treatment chair to an electrical receptacle may extend therethrough, and since the electrical conductor means extends through the base and the turntable at the axis thereof, it is apparent that the turntable may be adjusted about its vertical axis relative to the base without being unduly encumbered by the electrical conductor means.

It is another object of this invention to provide a pedestal construction for a treatment chair of the character described wherein improved means are provided for releasably locking the turntable against rotation relative to the base and comprises a brake arm carried by the body of the turntable and extending generally at a right angle to an imaginary radius line of the turntable, with the brake arm being engaged by a manually operable cam means carried by the turntable for forcing the brake arm outwardly relative to the body of the turntable and against the wall of the recess in the base so as to lock the turntable in the desired adjusted position relative to the base.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds when taken in connection with the accompanying drawings, in which FIG. 1 is a side elevation of a typical treatment chair having electrically operable components, including an elevatable and horizontally traversable seat, a tiltable backrest and a tiltable leg rest with the seat mounted on a standard and the standard mounted on the improved pedestal construction of the present invention;

FIG. 2 is an enlarged fragmentary view of the lower portion of FIG. 1;

FIG. 3 is a plan view, partially in section, taken substantially along line 3-3 in FIG. 2;

FIGS. 4, 5 and 6 are enlarged fragmentary vertical sectional views taken substantially along the respective lines 4-4, 55 and 6-6 in FIG. 3;

FIG. 7 is an exploded perspective view of the pedestal construction shown in FIG. 3, but omitting the standard and electrical operable components of the treatment chair;

FIG. 8 is an enlarged fragmentary plan view, partially in section showing a portion of the turntable and the associated locking cam for frictionally locking the turntable in the desired adjusted position relative to the pedestal base; and

FIG. 9 is an enlarged fragmentary vertical sectional view taken substantially along line 9-9 in FIG. 7.

Referring more specifically to the drawings, the numeral l broadly designates the improved pedestal construction, shown in FIG. 1 in association with a treatment chair 11 of a type having a seat 12, a pivoted or tiltable backrest l3 and a pivoted or tiltable leg rest 14. It is preferred that seat 12 is mounted on a substantially horizontally traversable carriage 15, and that the backrest and leg rest are pivotably connected to respective rear and front portions of seat 12 and/or its carriage 15. In either event, the seat 12, backrest 13 and leg rest 14 are raised and lowered with carriage 15 by a suitable elevator means 16 shown in FIGS. 1 and 2 in the form of parallelogram linkages 16a connecting a standard 20 of the chair 11 to a supporting elevator frame 21 on which carriage 15 is mounted.

Although the invention is not limited thereto, the treatment chair thus far described is of a type disclosed in a copending application of common assignee, Ser. No. 257,743, filed May 30, 1972, and entitled POWER OPERATED TREATMENT CHAIR, now US. Pat. No. 3,804,460, to which reference is made for a more detailed description thereof. As disclosed in said copending application, backrest l3 and leg rest 14 are tilted or pivoted relative to seat 12 by suitable connections with an electric motor which is designated at 60 in FIG. 7 of said copending application, but which is designated at 13a and is only shown schematically in FIG. 1 of this application.

Additionally, it will be observed in FIG. 1 that carriage 15 is traversed forwardly and rearwardly relative to the supporting elevator frame 21 by suitable connections with an electric motor shown schematically at 15a. Here again, the connections between carriage 15 and its electric motor 15a may be substantially the same as disclosed in said copending application wherein it will be observed that the comparable carriage is indicated at 24 and the electric motor for driving the same is indicated at 65. Accordingly, a more detailed description of the connections between backrest 13 and motor 13a and between carriage 15 and motor 15a of FIG. 1 is deemed unnecessary. It should be noted, however, that the motors 13a, 15a, as well as an additional elevator operating reversible electric motor 21a are electrically connected to and operated by suitable switches, such as are indicated at 13b, 15b, 21b, respectively, carried by the tiltable backrest 13 in FIG. 1.

Referring now to electric motor 21a, it will be observed in FIG. 2 that the housing of motor 21a is pivotally connected, as at 21c, to one of the links of the elevator linkages 16a of elevator means 16. The electric motor 21a is drivingly connected to a nut 21d, as by suitable gearing 212, for rotating the nut 21d in meshing engagement with a screw 21f. The lower end of screw 21 f is pivotally connected, as at 213, to a bracket (FIGS. 1, 2, 3, 4 and 7). Nut 21d is carried by a ho]- low arm 21h also pivoted at 21c with motor 21a. Thus, rotation of nut 21d, as effected by motor 21a, raises or lowers seat 12, backrest 13 and leg rest 14.

Both the standard20 and bracket 30 are suitably secured to the uppersurface of a turntable broadly designated at 35, which is part of the pedestal construction 10 and preferably is in the form of a relatively thin circular plate fitting in a substantially circular recess of a relatively thin pedestal base broadly designated at 36. As best shown in FIG. 3, standard 20 is in the form of a pair of laterally spaced upright plates 20a which are spaced substantially equidistantly astraddle opposite sides of the axis of rotation of turntable 35 with their rear portions straddling and spaced from opposite sides of bracket 30.

The particular manner in which the plates 20a of standard 20 are secured to the upper surface of tumtable 35 is not significant insofar as the present invention is concerned. However, it is important to note that screws 30a, which secure bracket 30 to the upper surface of turntable 35, are positioned on one side only of the plane of a lateral slot 35a which extends generally at a right angle to an imaginary radius line of the tumtable and whose entire length is disposed closely adjacent the periphery of turntable 35. Slot 35a is open at only one end thereof and divides turntable 35 into a main body 35b and a friction brake arm 350. It is to be noted that brake arm 350 has an outer peripheral surface remote from the turntable axis which is normally positioned within a circular plane corresponding substantially to the circumference of the periphery of the body 35b of turntable 35. In this instance, the screws 30a which fasten bracket 30 to turntable 35 are positioned so that they are threadedly embedded in the body 35b of turntable 35.

As heretofore indicated, turntable 35 has at least a peripheral portion thereof, and preferably the full thickness of its periphery, loosely fitting for rotation within a recess in base 36. As shown in FIGS. 4, 6 and 7, the substantially circular recess in base 36 is indicated at 36a and is defined by a substantially circular wall 36a and a substantially planar bottom wall 36b.

An antifriction bearing means engages the bottom wall 36b of turntable-receiving recess 36a and supports turntable 35 for rotation on bottom wall 36b. To this end, the lower surface of turntable 35 is provided with an annular groove or bearing race 35d therein of relatively large diameter. Preferably, groove 35d has a mean diameter within about to of the diameter of circular wall 36a in pedestal base 36. A circular series of steel balls 352 is loosely received in annular groove 35d. However, the depth of annular groove 35d is substantially less than the diameter of each ball 35e so that the lower surface of the turntable is maintained in spaced relation from the bottom wall 36b of the recess 36a in the base 36 when the balls 35c rest upon bottom wall 36b and turntable 35 rests upon balls 35e. In this regard, it is preferred that the substantially planar bottom wall 36b of the recess 36a is provided with an upwardly projecting annular ridge or race 362 engaged by the balls 35e and which facilitates the machine-finishing of pedestal base 36.

An annular fastening means surrounds the rotational axis of turntable 35 and includes means for maintaining turntable 35 in recess 36a and against the antifriction bearing balls 35e while permitting rotation of turntable 35 and the standard 20 thereon relative to base 36. Accordingly, it will be observed in FIGS. 5 and 7 that the central portion of the bottom wall 36b of recess 36a has a relatively small upwardly projecting portion or boss 36f integral therewith which is provided with a centrally disposed or axial hole or opening 36f extending therethrough and also extending through the bottom wall 36b of recess 36a.

The boss 36f is loosely received within a central or axial opening 35f of turntable 35 which is counterbored, as at 35g, to receive therein a suitable thrust bearing 35h. Bearing 35h preferably is in the form of a roller-type antifriction bearing whose upper end or race is engaged by a shouldered disk or cap 35j. The cage for the rollers of thrust bearing 35h, as well as the lower and upper races of bearing 35h are of sufficiently large inside diameter so as to permit passage of a plurality of circularly arranged screws 35k therethrough for securing cap 35 against the upper surface of the boss 36f projecting upwardly from the bottom wall 36b of recess 36a. Thus, cap 35j holds the antifriction thrust bearing 35h against the upper surface of the shoulder defined by the bore 35f and the counterbore 35g in turntable 35 and thereby maintains turntable 35 in recess 36a and against the antifriction bearing balls 35e while permitting free rotation of turntable 35 and the standard thereon relative to base 36. Also, it will be observed that the central portion of cap j. has an opening 35j therethrough which is axially aligned with opening 36] in the boss 36f so that turntable 35 and the fastening means therefor collectively define an axial opening therethrough.

The base 36 is provided with a substantially radially extending passageway 40 therein which is in the form of a shallow trough extending along the bottom surface of base 36. One end of passageway 40 communicates with the axial opening 35f in boss 36f, and the passageway 40 extends outwardly from the axial opening 36] along the bottom wall of the recess 36a and forms an orifice 40a communicating with the atmosphere at the forwardmost lower edge portion of the base 36 at a point spaced radially outwardly from turntable 35.

It will be observed in FIGS. 1 and 3 that one end of a pliable electrical cable or conduit 42 has a conventional electrical connector or plug 43 thereon adapted to be plugged into a conventional electrical receptacle or outlet, not shown. The pliable electrical cable 42 contains a plurality of electrical conductors a, b, c therein. Conductor a preferably is in the form of a neutral or ground conductor, and the conductors b, c, are in the form of power conductors or leads. It will be noted that cable 42 extends into orifice 40a, then along a portion of the passageway 40, and then upwardly through an opening 45 formed in the bottom wall of a shallow junction box recess 46 also formed in the base 36 forwardly of recess 36a. Within the junction box recess 46 ground conductor a is secured, as by a screw 46a, to pedestal base 36.

Also, within the junction box recess 46, the three conductors a, b, c are coupled or otherwise attached to respective conductors a, b, c which then extend downwardly through an opening 47 in the bottom wall of the recess 46 and then pass along the passageway 40, upwardly through the opening 36f in boss 36f, then upwardly through the opening 35j in the cap 35j and thus over the upper surface of the turntable 35. A smalldiameter coil of from one to two turns then may be formed in the composite cable 42a within which the three small conductors or wires a, b, c are positioned. The cable 42a then extends outwardly, is clamped to turntable, as by clamps 35k, and is connected through a suitable terminal bar 50 to corresponding electrical conductors or wires a", b", c". Conductors a", b", c" enter the lower end of a spirally wound, coiled or spring-like cable 51 having its lower end suitably clamped upon turntable 35. The upper end of the spirally wound cable 51 is suitably attached to the upper portion of the elevator frame 21, and the conductors or wires 0', b", c" extend from the upper end of cable 51 through a suitable electrical circuit, not shown, to the electric motors 15a, 13a, 21a (FIG. 1) and in which circuit the manual control switches l3h, 15b, 21b are interposed, as heretofore indicated.

As shown in FIGS. 3, 6 and 7, the junction box recess 46 in the upper forward portion of pedestal base 36 may be closed by a suitable removable cover plate 46b which may fit within a suitable, shallow, enlarged recess aligned with the junction box recess 46 so that the upper surface of cover 46b may be substantially flush with the upper surface of the corresponding portion of pedestal base 36. Also, it will be observed in FIGS. 5, 6, 7 and 9 that the bottom of trough or passageway 40 is closed throughout its length by a suitably recessed, elongate, bottom cover plate 40b suitably removably secured to the lower surface of pedestal base 36.

As shown in FIGS. 2, 3 and 5 a suitable flanged cover 52 overlies and protects from dust and foreign objects the small coil of the pliable conductor cable 42a.which closely surrounds the axis of turntable 35 and rests thereupon. Closure cover 52 also overlies cap 35 so as to shield the axial openings 35j', 36], which extend through the cap 35] and the boss 36f (FIG. 7) from accumulations of dust and dirt therein.

Referring again to the friction locking means, of which the brake arm 35c of turntable 35 is a part (FIGS. 3, 4, 7, and 8), as best shown in FIGS. 7 and 8, the pedestal turntable 35 is provided with an opening 55 therethrough which is preferably circular with the axis thereof extending vertically through turntable 35. Opening 55 may extend perpendicular to the plane of slot 35a so that opposing halves of opening 55 are disposed in the body 35b and brake arm 35c, respectively, of pedestal turntable 35. An eccentric braking cam 56 is loosely positioned in opening 55 and is mounted in eccentric relation on the lower end of a shaft 57. Shaft 57 extends upwardly and is rotatably mounted in and penetrates through the bracket 30, where it has one end of a foot-operated crank lever 60 suitably secured thereon.

Cam 56 is so positioned with respect to lever 60 and opening 55 that brake arm 350 is in a relaxed condition when crank lever 60 projects substantially radially outwardly with respect to the axis of turntable 35 and overlies the corresponding portion of the body of pedestal base 36, as in FIGS. 1-4, 7 and 8. However, when the attendant or operator wishes to lock the turntable and the chair carried thereby in a selected adjusted position with respect to base 36, lever 60 is so positioned as to be readily engaged and moved in eithera clockwise or a counterclockwise direction by the foot of the operator or attendant. In so doing, since the cam 56 is eccentrically positioned with respect to the opening 55 (FIGS. 7 and 8), the cam then engages and biases outwardly the brake arm 350 so that it, in turn, will firmly and frictionally engage the peripheral wall 36a of the recess 36a in the base 36, thus locking turntable 35 in the desired adjusted position until such time as the lever 60 is returned to the neutral position by the operator or attendant.

From the foregoing description, it can be seen that the turntable 35 with the chair thereon may be readily and easily adjusted about its vertical axis and relative to the pedestal base 36 without the need for providing a large coil of surplus electrical cable on the floor adjacent the pedestal base in orderto permit such adjustment. Further, it can be appreciated that the turntable 35 may be adjusted through very nearly a full revolution or 360 of rotation without placing the electrical conductor means embodied in the cable 42a and the electrical conductors a, b, c, under undue stress such as to present an electrical hazard or as to rupture the electrical conductor means.

It should be noted that a physician or attendant would normally desire to be able to adjust the turntable and the chair 11 carried thereby through only approximately one revolution about the vertical axis thereof. Accordingly, it will be observed in FIGS. 2, 3, 6 and 7 that bracket 30 is provided with a lip 30b which projects outwardly beyond the vertical plane of the periphery of turntable 35 and serves as a movable abutment to the extent that it moves with the turntable 35. The outwardly projecting lip 30b is so positioned as to engage a stationary abutment 62 projecting upwardly from the front portion of, and preferably formed integral with, pedestal base 36. Thus, it can be seen that the turntable 35 may be adjusted very nearly 360 in either direction; i.e., to the extent limited by the width of the lip 30b of bracket 30 and the width of the abutment 62. In practice, it has been found that the chair 11 and turntable 35 may be adjusted through an arc of at least about 350 relative to base 36, which is more than ample for all practical purposes.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

That which is claimed is:

1. A pedestal construction for a treatment chair, such as a dental chair, of the type having a standard and associated electrically operable components thereon; said pedestal construction comprising:

a base adapted to rest upon a supporting floor and having a substantially circular recess in its upper face and also having a bottom wall defining the bottom of said recess,

a turntable supporting thereon the standard of said treatment chair and having at least a peripheral portion thereof loosely fitting for rotation within the recess in said base,

fastening means adjacent the rotational axis of said turntable and including means maintaining said turntable in said recess while permitting rotation of said turntable and the standard relative to said base,

said turntable and said fastening means defining an axial opening therethrough,

said base having a passageway therein communicating with said axial opening and extending outwardly therefrom along said bottom wall of said recess and also forming an orifice in said base communicating with the atmosphere at a point radially outwardly of said turntable, and

said opening and passageway being adapted to accommodate electrical conductor means therethrough in its course from said electrically operable components to a source of electrical energy and permitting substantial turning of said turntable relative to said base without undue twisting of the conductor means.

2. A pedestal construction according to claim 1, in-

cluding antifriction bearing means engaging said bottom wall and circularly arranged around and in substantially spaced relation from said axis of said turntable, and said turntable being supported for rotation upon said antifriction bearing means.

3. A pedestal construction according to claim 2, wherein said antifriction bearing means comprises a circular series of steel balls, the lower surface of said turntable having an annular groove therein for loosely receiving said series of balls therein but being of substantially less depth than the diameter of each ball so that the lower surface of said turntable is maintained in spaced relation from said bottom wall of said recess in said base.

4. A pedestal construction according to claim 3, wherein the mean diameter of said series of balls is substantially less than the internal diameter of said circular recess.

5. A pedestal construction according to claim 3, wherein the mean diameter of said series of balls is within about to of the internal diameter of said circular recess.

6. A pedestal construction according to claim 1, wherein said fastening means comprises an annular antifriction bearing engaging an upper surface portion of said turntable surrounding said axial opening, a cap member having a central hole therethrough and engaging the upper surface of said annular antifriction bearing, and means securing said cap member in fixed relation to said bottom wall of said recess and in engagement with the upper surface of said annular antifriction bearing.

7. A pedestal according to claim 1, wherein said base is provided with a relatively small junction-boxdefining recess therein spaced radially from said tumtable and overlying a portion of and also communicating with said passageway whereby two otherwise separate conductors may be interconnected within said junction-box-defining recess.

8. A pedestal construction according to claim 1, wherein at least one pliable conductor cable extends along said passageway and through said axial opening, there .being at least one free loop coil of said pliable conductor cable positioned on said turntable and encircling the vertical plane of said axial opening, with an additional stretch of said conductor cable extending generally radial from said coil and secured to said turntable.

9. A pedestal construction according to claim 1, wherein said base includes a substantially circular wall defining the perimeter of said recess, and said turntable comprises a body, means for releasably locking said turntable against rotation relative to said base and comprising:

a brake arm carried by said body of said turntable and extending generally at a right angle to an imaginary radius line of said turntable,

said brake arm having an outer surface remote from said turntable axis and normally positioned within a circular plane corresponding substantially to the circumference of said peripheral portion of said turntable, and

a manually operable cam means carried by said turntable and engageable with said brake arm for forcing said brake arm outwardly relative to said body and against said circular wall to lock said turntable in the desired position relative to said base.

10. A pedestal construction according to claim 9,

11. A pedestal construction for a treatment chair,

such as a dental chair, of the type having a standard and associated electrically operable components; said pedestal construction comprising:

a base adapted to rest upon a supporting floor and having a substantially circular recess in its upper face and also having a bottom wall defining the bottom of said recess,

a turntable for supporting thereon the standard of said treatment chair and having at least a peripheral portion thereof loosely fitting for rotation within the recess in said base,

antifriction bearing means engaging the bottom wall of said recess and supporting said turntable for rotation thereon,

annular fastening means closely surrounding the rotational axis of said turntable and including means maintaining said turntable in said recess against said antifriction bearing means while permitting rotation of said turntable and the standard thereon relative to said base,

said turntable and said fastening means defining an axial opening therethrough,

said base having a passageway therein adjacent said fastening means and communicating with said axial opening, and said passageway extending outwardly from said axial opening along said bottom wall of said recess and forming an orifice communicating with the atmosphere at a point radially outwardly of said turntable, and

an electrical conductor cable means extending through said opening and passageway in its course from said electrically operable components to a source of electrical energy.

12. A pedestal construction for a treatment chair,

such as a dental chair, of the type having a standard and 10 associated relatively movable chair components; said pedestal construction comprising:

a base adapted to rest upon supporting floor and having a substantially circular wall defining a recess in its upper face and also having a bottom wall defining the bottom of said recess,

a turntable including a body supporting thereon the standard of said treatment chair and having at least a peripheral portion thereof loosely fitting for rotation within the recess in said base, and

means for releasably locking said turntable against rotation relative to said base and comprising,

a brake arm carried by said body of said turntable and extending generally at a right angle to an imaginary radius line of said turntable,

said brake arm having an outer surface remote from the axis of said turntable and normally positioned within a circular plane corresponding substantially to the circumference of said peripheral portion of said turntable body, and

a manually operable cam means carried by said turntable and engageable with said brake arm for forcing said brake arm outwardly relative to said body and against said circular wall to lock said turntable in the desired position relative to said base. 

1. A pedestal construction for a treatment chair, such as a dental chair, of the type having a standard and associated electrically operable components thereon; said pedestal construction comprising: a base adapted to rest upon a supporting floor and having a substantially circular recess in its upper face and also having a bottom wall defining the bottom of said recess, a turntable supporting thereon the standard of said treatment chair and having at least a peripheral portion thereof loosely fitting for rotation within the recess in said base, fastening means adjacent the rotational axis of said turntable and including means maintaining said turntable in said recess while permitting rotation of said turntable and the standard relative to said base, said turntable and said fastening means defining an axial opening therethrough, said base having a passageway therein communicating with said axial opening and extending outwardly therefrom along said bottom wall of said recess and also forming an orifice in said base communicating with the atmosphere at a point radially outwardly of said turntable, and said opening and passageway being adapted to accommodate electrical conductor means therethrough in its course from said electrically operable components to a source of electrical energy and permitting substantial turning of said turntable relative to said base without undue twisting of the conductor means.
 2. A pedestal construction according to claim 1, including antifriction bearing means engaging said bottom wall and circularly arranged around and in substantially spaced relation from said axis of said turntable, and said turntable being supported for rotation upon said antifriction bearing means.
 3. A pedestal construction according to claim 2, wherein said antifriction bearing means comprises a circular series of steel balls, the lower surface of said turntable having an annular groove therein for loosely receiving said series of balls therein but being of substantially less depth than the diameter of each ball so that the lower surface of said turntable is maintained in spaced relation from said bottom wall of said recess in said base.
 4. A pedestal construction according to claim 3, wherein the mean diameter of said series of balls is substantially less than the internal diameter of said circular recess.
 5. A pedestal construction according to claim 3, wherEin the mean diameter of said series of balls is within about 75% to 85% of the internal diameter of said circular recess.
 6. A pedestal construction according to claim 1, wherein said fastening means comprises an annular antifriction bearing engaging an upper surface portion of said turntable surrounding said axial opening, a cap member having a central hole therethrough and engaging the upper surface of said annular antifriction bearing, and means securing said cap member in fixed relation to said bottom wall of said recess and in engagement with the upper surface of said annular antifriction bearing.
 7. A pedestal according to claim 1, wherein said base is provided with a relatively small junction-box-defining recess therein spaced radially from said turntable and overlying a portion of and also communicating with said passageway whereby two otherwise separate conductors may be interconnected within said junction-box-defining recess.
 8. A pedestal construction according to claim 1, wherein at least one pliable conductor cable extends along said passageway and through said axial opening, there being at least one free loop coil of said pliable conductor cable positioned on said turntable and encircling the vertical plane of said axial opening, with an additional stretch of said conductor cable extending generally radial from said coil and secured to said turntable.
 9. A pedestal construction according to claim 1, wherein said base includes a substantially circular wall defining the perimeter of said recess, and said turntable comprises a body, means for releasably locking said turntable against rotation relative to said base and comprising: a brake arm carried by said body of said turntable and extending generally at a right angle to an imaginary radius line of said turntable, said brake arm having an outer surface remote from said turntable axis and normally positioned within a circular plane corresponding substantially to the circumference of said peripheral portion of said turntable, and a manually operable cam means carried by said turntable and engageable with said brake arm for forcing said brake arm outwardly relative to said body and against said circular wall to lock said turntable in the desired position relative to said base.
 10. A pedestal construction according to claim 9, wherein said turntable is provided with a relatively narrow slot therethrough defining the proximal edges of said body and said brake arm and also wherein said brake arm is provided with a free end and is integral at its other end with said turntable body.
 11. A pedestal construction for a treatment chair, such as a dental chair, of the type having a standard and associated electrically operable components; said pedestal construction comprising: a base adapted to rest upon a supporting floor and having a substantially circular recess in its upper face and also having a bottom wall defining the bottom of said recess, a turntable for supporting thereon the standard of said treatment chair and having at least a peripheral portion thereof loosely fitting for rotation within the recess in said base, antifriction bearing means engaging the bottom wall of said recess and supporting said turntable for rotation thereon, annular fastening means closely surrounding the rotational axis of said turntable and including means maintaining said turntable in said recess against said antifriction bearing means while permitting rotation of said turntable and the standard thereon relative to said base, said turntable and said fastening means defining an axial opening therethrough, said base having a passageway therein adjacent said fastening means and communicating with said axial opening, and said passageway extending outwardly from said axial opening along said bottom wall of said recess and forming an orifice communicating with the atmosphere at a point radially outwardly of said turntable, and an electrical conductor cable means extending through said opening and passageway in its course from said electrically operable components to a source of electrical energy.
 12. A pedestal construction for a treatment chair, such as a dental chair, of the type having a standard and associated relatively movable chair components; said pedestal construction comprising: a base adapted to rest upon supporting floor and having a substantially circular wall defining a recess in its upper face and also having a bottom wall defining the bottom of said recess, a turntable including a body supporting thereon the standard of said treatment chair and having at least a peripheral portion thereof loosely fitting for rotation within the recess in said base, and means for releasably locking said turntable against rotation relative to said base and comprising, a brake arm carried by said body of said turntable and extending generally at a right angle to an imaginary radius line of said turntable, said brake arm having an outer surface remote from the axis of said turntable and normally positioned within a circular plane corresponding substantially to the circumference of said peripheral portion of said turntable body, and a manually operable cam means carried by said turntable and engageable with said brake arm for forcing said brake arm outwardly relative to said body and against said circular wall to lock said turntable in the desired position relative to said base. 